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Retention basin outlet fittings

02-07-2014, 07:44 AM

These parts go on a concrete outlet structure. I didn't design it, just working off not so great prints. Some guess work involved. I'll post new pics as I go. First pc. is a cone shaped pc. for the bottom drain hole. 304 ss. Started with 1/8" sheet. Layed out & cut two halves, then bumped to shape. Tacked together. You can see the lines I drew for bumping, about 1" apart on large end. you can make the cone smoother or not by bumping closer/farther apart. Cone is 12"h x 9"lrg end x 3"sm end.

I still need to cap off the large end & add an inlet box to the side. Then it gets welded to a mounting plate that bolts to the concrete structure.

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Started with 1/8" sheet. Layed out & cut two halves, then bumped to shape. Tacked together. You can see the lines I drew for bumping, about 1" apart on large end. you can make the cone smoother or not by bumping closer/farther apart.

I've got a question - I just do backyard stuff and it's always just square cut stuff. I've always wanted to be able to make shapes from sheet. I don't understand what you mean by "bumping" and I'd love to know if it's easy to form shapes like this - how do you do it? Because there are a bunch of uses I could have for cones, funnels, semicircles, spheres, hemispheres, whatever.

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Bumping is a term used for making a shape (such as a radius) by bending it in several places. If you look at my second pic you will see numerous lines on the pcs. Each line represents a bend. I did these on a small brake in my press. The lines would all intersect at one point which would be the theoretical point of the cone.

To make a complete circle/cylinder you need 360 degrees. Each half would then be 180 degrees. I have 12 bend lines on each half. So I bent the pc. on each line approximately 15 degrees. 12 bends at 15 degrees = 180 degrees.

If I made more bend lines closer together then more bends of less degrees equals a smoother pc. Likewise if I only used 4 bends per pc. it would look like an octagon instead of a circle. Most times I do this it is just a judgment on my part as to how smooth I want it. I just happened to get 12 lines on this because I spaced the lines about 1 inch apart on the large end.

I don't have time right now to explain how I lay out a cone, maybe another day. I'm sure if you search on the internet you can find a tutorial on it.

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Thanks guys. I did a search and seems a press would come in handy. Unfortunately I don't have one yet so I'll have to wait. A few people use home made jigs and hammers to bump shapes, but I doubt my residential neighbours would appreciate the noise. Once I get some spare time I might think about expanding my workshop with rollers or a press, maybe home made.

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Wow a 52" hand roller? I wonder what thickness you can do? I have a 36" powered roll but with 4" rolls I wouldn't be able to get the small end of the cone. Besides small cones like this are tough to get them to roll correctly. When rolling a cone you have to get it to rotate as it goes through so the rolls are always parallel with the center lines.

Even if your bumping is slightly off once the cone is tacked you can hammer it around to get it to even out.

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A couple years back I built something for an up grade / expansion of a local water treatment plant that had a SS conical section (reducer) in it. All though the cone came to me premade it was made the same way you built yours. Who ever built it definetly knew what they were doing and had some good equipment to do it with because it was a really smooth job of bumping a radius into two pieces of 1/4" flat plate.

Will Argue for Beer (any issue, either side)

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Finished up the rest of the items for this job. 1/2" aluminum plate with hole, 1/2" aluminum weir plate with grating, trash rack (grating with mounts) & locking bar for existing top grating. Everything gets mounted to a concrete outlet structure (drain for retention pond). The trash rack was built in two sections as it is 161" long x 48" wide. The angles bolt to the concrete & the bar grating bolts to the angles. They need access to clean it out once in awhile.

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I think what may have been specified on the plan is what is called a Hydrobrake or Fluidic Cone. They are made by Contech, but I am sure other companies make them now. It allows water leaving the basin to swirl thru and leave at a slower rate.

Thought you may want to see pictures/specs to compare it to what you made which looks awesome.